DIY in France; science class in Luton

Following my younger daughter's recommendation that I celebrate the sheer painlessness of the DVLA's online tax disc sysem (See, Goodbye to the golden era of vehicle licensing, May 12) I have two suggestions from my older daughter.

Tell them about the set-square, she says. Another Anglo-French moment. Yet again I was engaged in DIY at the house in Loire Atlantique and needed a set-square. A translation exists (l'équerre à dessin) although it looks suspect - sounds more like a T-square. Anyway I didn't have the translation to hand. At the bricolage, I described a set-square's appearance and - rather more demandingly - its function. The assistant listened then said, charmingly,"It sounds like a good idea." But admitted he hadn't got one. There was one in a bubble-pack at the next bricolage.

My older daughter is a teacher's assistant on the science side and her second suggestion relates to my post on Ohm's Law (see Introducing two mega-stars, May 6). Teacher: "Resistance boys, what is resistance?" Class: Blank looks, silence. Teacher: "Imagine I'm outside Burger King and I want to get to Debenhams. At 7 am this would be easy. At 3 pm on a Saturday it would be much harder. Do you see what I mean?"

My daughter adds the coda: So when did resistance have a proportional relationship with time?

NOTE The set-square shown is not the jazzy yellow and chrome one I bought in France. This one belonged to my grandfather, possibly my great-grandfather.